(a) Why are decomposition reactions called the opposite of combination reactions? Explain with equations of these reactions.
(b) Express the following facts in the form of a balanced chemical equation:
“When a strip of copper metal is placed in a solution of silver nitrate, metallic silver is precipitated and a solution containing copper nitrate is formed”.
(a) Those reactions in which a compound splits up into two or more simpler substances are known as decomposition reactions.
Example: When calcium carbonate is heated, it decomposes to give calcium oxide and carbon dioxide.
They are called opposite of combination reactions because in a combination reaction, two or more substances combine to form a single substance.
Example: Magnesium and oxygen combine, when heated, to form magnesium oxide.
(b) Cu (s) + 2AgNO3 (aq)→ Cu(NO3)2 (aq) + 2Ag (s)
CaCO3(s) + Heat + (Decomposition) → CaO(s) + CO2(g)
They are called opposite of combination reactions because in a combination reaction, two or more substances combine to form a single substance.
Example: Magnesium and oxygen combine, when heated, to form magnesium oxide.
2Mg(s) + O2 + Combination → 2MgO(s)